<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS demo</title>
    <style>
        $primary-color: darkred;

        .title1 {
            color: $primary-color;
        }

        .content1 {
            color: gray;
        }

        .title2 {
            color: $primary-color;
        }

        .content2 {
            color: gray;
        }
    </style>
</head>
<body>
<div class="main">
    <p class="title1">主标题</p>
    <div class="content1">
        这是一段长文本，很长很长...
    </div>
</div>

<div class="secondary">
    <p class="title2">另一个主标题</p>
    <div class="content2">
        这是“另”一段长文本，很长很长...
    </div>
</div>
</body>
</html>